1. Field of the Invention
The present invention relates to communication networks and, more particularly, to a method and apparatus for detecting unsolicited multimedia communications.
2. Description of the Related Art
Data communication networks may include various routers, switches, bridges, hubs, and other network devices coupled to and configured to pass data to one another. These devices will be referred to herein as “network elements.” Data is communicated through the data communication network by passing protocol data units, such as Internet Protocol (IP) packets, Ethernet Frames, data cells, segments, or other logical associations of bits/bytes of data, between the network elements by utilizing one or more communication links between the devices. A particular protocol data unit may be handled by multiple network elements and cross multiple communication links as it travels between its source and its destination over the network.
As communication networks have proliferated, corporations and individuals have become reliant on the networks for many different types of communication services. One type of common communication service is the ability to transmit e-mail messages on the network. Since transmission of e-mail messages is generally free, fast, and reliable, e-mail has become a very popular way of communicating over a communication network.
Unfortunately, many individuals and corporations determined that e-mail would be a cheap way of advertising particular products, both wanted and unwanted. Accordingly, e-mail has become commonly used to send unsolicited information. Unsolicited e-mail is commonly referred to as SPAM, and may take many forms, although SPAM generally is of a commercial nature and is sent in bulk form to many recipients. The transmission of SPAM on the Internet has increased to such an extent that at one point it was estimated that about 90% of all e-mail traffic on the Internet was SPAM.
Because of the proliferation of SPAM, many e-mail services and network providers are beginning to provide anti-SPAM screening products and services. These products generally filter SPAM at an email server or at the user's personal computer so that the unsolicited e-mail messages do not get grouped together with other legitimate e-mail messages. SPAM filters generally detect SPAM messages by looking at the sender's source address, the subject line of the e-mail message, and other aspects of the e-mail.
Initially, voice communications were carried on a voice network, and data communications such as e-mail were carried on a separate data (Internet Protocol or IP) network. For various reasons, those networks are being consolidated so that voice calls may be made over data networks using a protocol commonly referred to as Voice over IP (VoIP). VoIP uses the Session Initialization Protocol (SIP) or other signaling protocol to establish a voice call on an IP network, and then uses the transport facilities of the IP network to enable the parties to talk in the same manner as would occur if the voice call had been connected over the voice network.
Although VoIP has the potential to reduce the costs associated with making telephone calls, it also potentially presents a new problem. Specifically, the reduction in cost and difficulty of making an Internet based telephone call has provided an opportunity for SPAM to be delivered over Internet Telephony. Thus, Internet telephony may potentially be abused in the future in the same manner that e-mail has been abused on the current networks. Unfortunately for telephone users, Spam over Internet Telephony (SPIT) is likely to be more intrusive than SPAM has been, since SPIT has the potential to cause a telephone to ring at the user's place of business or home in real time. Thus, unlike SPAM which may be ignored, SPIT has the potential to be quite intrusive.
Other forms of SPAM are also being developed. For example, SPAM over Instant Messaging (SPIM), SPAM over Fax (SPAF), have been reported. Additionally, if video telephony becomes prominent, it is possible that that new media may become abused to transmit SPAM video messages. Accordingly, it would be advantageous to provide a system that could filter multiple types of SPAM.